Abstract: A new method using immunoaffinity chromatography (IAC) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was established for the determination of diarrhetic shellfish poisons (DSP) such as okadaic acid (OA), dinophysistoxin-1 (DTX1), pectenotoxin-1 (PTX1) in shellfish. Samples were extracted with 80% methanol, diluted with phosphate buffer, cleaned up by immunoaffinity chromatography, and detected by LC-MS/MS. The major parameters affecting the performance of IAC, including loading amount, washing time and elution conditions, were investigated. Detection was carried out by electrospray ionization in the negative ion mode using multiple reaction monitoring (MRM). The linear range of the analytes was 1.0–100 μg/L with correlation coefficient more than 0.996. The limit of detection (LOD) and limit of quantification (LOQ) for the analytes were calculated as 0.3 and 1.0 μg/kg, respectively. The mean recoveries of the analytes were in the range of 82.7%–94.3% with a relative standard deviation (RSD) of less than 7.61%. Therefore, the method could be used to identify and quantify diarrhetic shellfish poisons in shellfish with less matrix interference and satisfactory sensitivity.

Key words: immunoaffinity chromatography (IAC), liquid chromatography-tandem mass spectrometry (LC-MS/MS), diarrhetic shellfish poison